I've used Macs for years (mostly the same one bought when I was a lot better off) and I find them much more secure and robust than Windows machines (less irritating too) but to be honest if I were needing to get a new machine now I'd probably get machine without anything and install Ubuntu.
For one thing you can get a large sum knocked off with some dealers for not having Windows pre-installed.
Almost any application you can imagine has an open source cousin which costs nothing and it's just as secure (if not more) as a Mac but as cheap any machine that would run Windows.
The number of relatives and friends I have with machines clogged up with malware and viral attacks or sitting on expensive applications that they can no longer upgrade without forking out even more money is shocking.
Their usual response is to throw the machine away when it would work perfectly well for their needs if they only purged Windows and went over to Linux (they could continue to run most of their Windows apps through Wine).
I recommend anyone to try it (you can install it on a partition and keep Windows if you must or even try it out from a flash RAM or a DVD).
You can even make the system look and feel like Windows or OS X if you like.
Like moving over to any browser but Internet Exploder you have nothing to lose but your chains.